挪威上空的全圆彩虹

2022年12月27日

A Full Circle Rainbow over Norway
Image Credit & Copyright: Lukas Moesch

Explanation: Have you ever seen an entire rainbow? From the ground, typically, only the top portion of a rainbow is visible because directions toward the ground have fewer raindrops. From the air, though, the entire 360-degree circle of a rainbow is more commonly visible. Pictured here, a full-circle rainbow was captured over the Lofoten Islands of Norway in September by a drone passing through a rain shower. An observer-dependent phenomenon primarily caused by the internal reflection of sunlight by raindrops, the rainbow has a full diameter of 84 degrees. The Sun is in the exact opposite direction from the rainbow’s center. As a bonus, a second rainbow that was more faint and color-reversed was visible outside the first.

Tomorrow’s picture: open space

挪威上空的全圆彩虹
图像提供与版权: Lukas Moesch

说明: 你看过完整的彩虹吗？在地面上，因为靠近地面方向的雨滴较少，通常只能见到彩虹的上半部。然而当飞行在天空之时，反而较常看到360度的全圆彩虹。上面这幅图像，呈现了今年9月一架无人机穿过一场阵雨时，在of挪威罗弗敦群岛上空所记录的一例全圆彩虹。这种现象端视观察者所在的位置而异、主要因为雨滴对阳光的内反射所产生的全圆彩虹，其直径（视张角）为84度。太阳与彩虹中心的方向相反。作为奖励，在第一个彩虹之外可以看到第二个更微弱和颜色反转的彩虹。这种因观察者所在位置而异的现象，形成的主因是雨滴内反射阳光所致。随直升机移动的这圈彩虹，张角为84度，大小则约有5公里。作为额外的奖励，更可在主虹的外侧，见到较暗、色泽排列相反的霓（次虹）。

明日的图片: open space